Can't see all Gradle's documentation diagrams

Hi, I tried with

Google Chrome 30.0.1599.101 m
FireFox 25.0.1
With Chrome if I click on the image and tried to scroll using visible scroll bar nothing happens but when I click on the image and use arrow keys the picture is moving. When I use FireFox it is extremely hard even to find the right place on the image to click on .I have to click 10 or 15 times until arrows starts working.

Wrong Picture

It would be better when I click on the image the scroll key on my mouse to work and to scroll the picture or at least the visible scroll to work.